title: In vitro studies on release and skin permeation of nonivamide from novel oil-in-oil-emulsions.
abstract: The purpose of this study was to develop oil-in-oil-emulsions that facilitate long-term treatment for chronic pruritus with capsaicinoids. To this end, oil-in-oil-emulsions, which comprised polydimethyl siloxanes, silicone surfactant and castor oil, were examined. We used nonivamide, a synthetic analogue of capsaicin as the active pharmaceutical ingredient. It was incorporated into castor oil that formed the dispersed phase of the emulsion. We evaluated the influence of formulation variables (nonivamide content, phase volume ratio and viscosity of the silicone oil) on the in vitro release and the permeation of nonivamide. Permeation was found to be controlled by the nonivamide concentration in the dispersed phase and the phase volume ratio. Oil-in-oil-emulsions were found to produce constant permeation rates over a period of 10h. They are thus superior to conventional semisolid formulations as application intervals may be extended.
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Tuebingen, Germany. Electronic address: rottke.michael@googlemail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Rottke
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Tuebingen, Germany. Electronic address: dominique.lunter@uni-tuebingen.de.
authors.forename: Dominique Jasmin
authors.initials: DJ
authors.lastname: Lunter
authors.affiliation: Department of Pharmaceutical Technology, Eberhard Karls University, Tuebingen, Germany. Electronic address: rolf.daniels@uni-tuebingen.de.
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniels
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D002368:Castor Oil / Q000737:chemistry / Q000378:metabolism; D004129:Dimethylpolysiloxanes / Q000737:chemistry / Q000378:metabolism; D004655:Emulsions / Q000737:chemistry / Q000378:metabolism*; D009821:Oils / Q000737:chemistry / Q000378:metabolism*; D010539:Permeability; D012828:Silicones / Q000737:chemistry / Q000378:metabolism; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism; D013552:Swine
chemical_list: D004129:Dimethylpolysiloxanes; D004655:Emulsions; D009821:Oils; D012828:Silicones; D013501:Surface-Active Agents; C013830:baysilon; D002368:Castor Oil; D002211:Capsaicin; C040937:nonivamide
keywords: Nonivamide; Oil-in-oil-emulsion; Permeation; Pig ear skin; Silicone oil; Topical delivery